[analyzer] Don't assert when mixing reinterpret_cast and derived-to-base casts.

This just adds a very simple check that if a DerivedToBase CastExpr is
operating on a value with known C++ object type, and that type is not the
base type specified in the AST, then the cast is invalid and we should
return UnknownVal.

In the future, perhaps we can have a checker that specifies that this is
illegal, but we still shouldn't assert even if the user turns that checker
off.

PR14872

llvm-svn: 175239

1 files changed, 28 insertions, 0 deletions

diff --git a/clang/test/Analysis/reinterpret-cast.cpp b/clang/test/Analysis/reinterpret-cast.cpp
index e82f7b68694..aaa600e4b96 100644
--- a/clang/test/Analysis/reinterpret-cast.cpp
+++ b/clang/test/Analysis/reinterpret-cast.cpp
@@ -18,3 +18,31 @@ void test(Data data) {
   wrapper->set();
   clang_analyzer_eval(wrapper->x == 42); // expected-warning{{TRUE}}
 }
+
+namespace PR14872 {
+  class Base1 {};
+  class Derived1 : public Base1 {};
+
+  Derived1 *f1();
+
+  class Base2 {};
+  class Derived2 : public Base2 {};
+
+  void f2(Base2 *foo);
+
+  void f3(void** out)
+  {
+    Base1 *v;
+    v = f1();
+    *out = v;
+  }
+
+  void test()
+  {
+    Derived2 *p;
+    f3(reinterpret_cast<void**>(&p));
+    // Don't crash when upcasting here.
+    // In this case, 'p' actually refers to a Derived1.
+    f2(p);
+  }
+}